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|
-- |
-- Module : Foundation.Primitives.Types.AsciiString
-- License : BSD-style
-- Maintainer : Haskell Foundation
-- Stability : experimental
-- Portability : portable
--
-- A AsciiString type backed by a `ASCII` encoded byte array and all the necessary
-- functions to manipulate the string.
--
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleContexts #-}
module Basement.Types.AsciiString
( AsciiString(..)
, MutableAsciiString(..)
-- * Binary conversion
, fromBytesUnsafe
, fromBytes
) where
import Basement.Compat.Base
import Basement.Compat.Semigroup
import Basement.Types.Char7
import Basement.UArray.Base
import qualified Basement.Types.Char7 as Char7
import qualified Basement.UArray as A (all, unsafeRecast)
-- | Opaque packed array of characters in the ASCII encoding
newtype AsciiString = AsciiString { toBytes :: UArray Char7 }
deriving (Typeable, Semigroup, Monoid, Eq, Ord)
newtype MutableAsciiString st = MutableAsciiString (MUArray Char7 st)
deriving (Typeable)
instance Show AsciiString where
show = fmap Char7.toChar . toList
instance IsString AsciiString where
fromString = fromList . fmap Char7.fromCharMask
instance IsList AsciiString where
type Item AsciiString = Char7
fromList = AsciiString . fromList
toList (AsciiString chars) = toList chars
-- | Convert a Byte Array representing ASCII data directly to an AsciiString without checking for ASCII validity
--
-- If the input contains invalid Char7 value (anything above 0x7f),
-- it will trigger runtime async errors when processing data.
--
-- In doubt, use 'fromBytes'
fromBytesUnsafe :: UArray Word8 -> AsciiString
fromBytesUnsafe = AsciiString . A.unsafeRecast
-- | Convert a Byte Array representing ASCII checking validity.
--
-- If the byte array is not valid, then Nothing is returned
fromBytes :: UArray Word8 -> Maybe AsciiString
fromBytes arr
| A.all (\x -> x < 0x80) arr = Just $ AsciiString $ A.unsafeRecast arr
| otherwise = Nothing
|
